Fabric tube type dust collector and method of operating the same



Nov. 16, 1965 J. ODELL 3,217,458

FABRIC TUBE TYPE DUST COLLECTOR AND METHOD OF OPERATING THE SAME FiledSept. 27, 1961 2 Sheets-Sheet 1 F J j/G MENTOR LEONARD J. O'DELLATTORNEY Nov. 16, 1965 J. ODELL FABRIC TUBE TYPE DUST COLLECTOR ANDMETHOD OF OPERATING THE SAME 2 Sheets-Sheet 2 Filed Sept. 27, 1961 TDIAll

LTDIC NCRB if U INVENTOR. LEONARD J. O'DELL ATTORNEY United StatesPatent 3,217,468 FABRIC TUBE TYPE DUST CGLLECTOR AND METHOD OF OPERATINGTHE SAME Leonard J. ODell, Louisville, Ky., assignor to American AirFilter Company, Inc, Louisville, Ky., a corporation of Delaware FiledSept. 27, 1961, Ser. No. 141,073 3 Claims. (Cl. 5596) The presentinvention relates to fabric gas cleaning devices and more particularlyto improved fabric tube type dust collectors and an improved method ofoperating the same.

Gas pervious fabric tube type dust collectors have long been known inthe gas cleaning industry as effective in removing various industrialair pollutant materials. Dirty gas streams to be treated have beenpassed through gas pervious fabric tubular collectors so thatcontaminant particles in the streams have been removed by the gaspervious fabrics, the contaminant particles collecting in cakes on theinternal surfaces of the fabric tubes. To periodically remove collectedcontaminant particles from the tubes so as to maintain appropriate gascleaning efficiencies, the fabric tubes have either been shaken withcomplex and expensive shaker mechanisms or have been collapsed andreinflated to break and dislodge the cakes of contaminant particles. Inthose instances where the tubes have been collapsed and reinflated inorder to accomplish suflicient contaminant particle removal, it has beenthe practice to so reinflate the tubes that the reinfiation cycleterminates with a violent snapping or popping action. Although pastarrangements for collapsing and reinflating the fabric tubes have provenreasonably efiicient when compared with shaker type tube cleaners, thepresent invention recognizes that these past arrangements also have hadtheir disadvantages. For one, the sudden snapping or popping at the endportion of a tube cleaning cycle has caused many of the contaminantparticles that have been collected by the tubes to be forced through thetubes rather than be released therefrom, these contaminant particlesbeing entrained in the clean gas stream during sub sequent operations.Moreover, the aforedescribed snapping or popping has resulted in decidedtube Wear and in wear of the supporting mechanism for the tubes. Thiswear has led to reduction in cleaning efliciency and has resulted incostly and time consuming repairs and replacements.

In accordance with the present invention, an improved fabric tube typedust collector and an improved method of operating the same is provided.The arrangement of the present invention avoids the abovementioneddisadvantages to provide a gas cleaning device which can be utilizedWhere greater efficiencies are desired and where high temperatureoperation is a factor, such as in the cement, steel or carbonindustries. With the arrangement of the present invention, thorough tubeflexing during tube cleaning operations is obtained without the violentshaking which has brought about fabric damage and which has reduced tubelife. Further, such thorough tube shaking is accomplished in a minimumof time and without the expensive and space consuming equipment requiredin the past.

Various other features of the present invention will become obvious toone skilled in the art upon reading the disclosure set forthhereinafter. More particularly, the present invention provides a methodof collecting contaminant particles from a dirty gas stream comprisingthe steps of passing the dirty gas stream in a first direction through agas pervious fabric collector zone at sufficient pressure and velocityto maintain the fabric collector in infiated form and to permitcontaminant particles in the dirty gas stream to collect in cake form onthe fabric collector, interrupting the flow of the dirty gas streamthrough the collector, passing a clean gas stream in a reverse directionthrough the collector at a sufiicient pressure and velocity to at leastpartially collapse the collector and crack the contaminant cake thereon,resuming the flow of the dirty gas stream in the first direction throughthe fabric collector for a time period less than that required to fullyreinflate the collector but at sufiicient pressure and velocity to allowthe collector to inertially fully reinflate in a softly flutteringmanner after the reverse flow of the gas stream has been interrupted,and interrupting the resumed flow of the dirty gas stream to bring aboutsuch inertial reinflation of the fabric collector, the period of dirtygas stream flow interruption being maintained a sufilcient time topermit such fabric fluttering with concomitant cracking, dislodging andgravity removal of contaminants from the fabric collector. In addition,the present invention provides a novel apparatus for carrying out theaforedescribed method, such apparatus including a housing having a dirtygas inlet, a reverse flow outlet and a clean gas outlet, gas perviousfabric tubular collector means resiliently mounted in the housing, thetubular collector means having a dirty gas inlet communicably connectedwith the dirty gas inlet and the reverse flow outlet of the housing, afirst damper for the dirty gas inlet of the housing, a second damper forthe reverse flow outlet of the housing, and control means for the firstand second dampers, the control means including a first timer arrangedto cause the closing of the primary damper for a preselected period oftime to shut off passage of dirty gas through the dirty gas inlet of thehousing and through the tubular collector means, a second timer arrangedto cause the opening of the second damper for a preselected period oftime when the first damper is closed to permit clean gas to pass throughthe tubular collector means to the reverse flow outlet of the housingthereby at least partially collapsing the collector means to initiallydislodge contaminant particles collected thereon and a third timerarranged to cause the closing of the primary damper for a preselectedperiod of time shortly after the first and second timer has timed outand before the filter tube means has been fully inflated whereby thetubular collector means inertially moves toward full inflation with anaccompanying fluttering movement to further crack and dislodgecontaminant particles collected thereon.

It is to be understood that various changes can be made in the shape,form and construction of the apparatus disclosed herein and in theseveral steps of the method disclosed herein without departing from thescope or spirit of the present invention. For example, although the present disclosure sets forth an upflow arrangement for tube type dustcollector, it is to be understood that the features of the inventionalso can be incorporated in a downflow arrangement. It further is to beunderstood that, although the present invention finds particularapplicability in industrial dust collection where contaminant particleconcentration and particle sizes are generally large, the presentinvention also can be utilized in gas cleaning conditions when particleconcentration and particle sizes are lessfor example, in atmosphericfiltration.

Referring to the drawings:

FIGURE 1 is a partially broken, exploded, elevational View of a gaspervious fabric tubular collector housing in which the inventiveimprovement is incorporated;

FIGURE 2 is an isometric view of the base support structure for thecollector housing of FIGURE 1; and,

FIGURE 3 is a schematic diagram of electrical circuitry incorporatingthe inventive improvement for operating the tubular collector structureof FIGURES 1 and 2.

Referring to FIGURE 1 of the drawings, tubular collector housing 2 isdisclosed as including a dirty gas inlet section 3, tube section 4,clean gas outlet section 5 having a clean gas outlet 10, hopper section6 and damper section 7. As can be seen in FIGURE 2 of the drawings, asuitable housing base support section 8 is provided to support theaforementioned housing 2.

In the embodiment of the invention disclosed, dirty gas inlet section 3is divided into four separate compartments by suitable partitions (notshown in detail) so that each compartment has a dirty gas inlet aperture9 and a reverse gas outlet flow aperture 11. It is to be understood thatthe present invention is not to be considered as limited to the numberof sections disclosed, the number of sections utilized depending uponsuch factors as the size of the unit, the number of tubes involved, andthe particular results desired in a specific application. Hopper section6 which is positioned below dirty gas inlet section 3 in communicablerelationship therewith, is arranged to communicate with each of thecompartments in section 3 and, as disclosed, includes a pair of rotaryvalves 12, 13 which can be timed to open and close in a preselectedmanner in accordance with the gas cleaning operations that are describedhereinafter.

To control flow of a dirty gas stream through each of dirty gas inletapertures 9 and into the separate compartments of dirty gas inletsection 3, solenoid controlled pneumatic damper sections 7 are provided.In the drawings, only one damper section 7, capable of handling twocompartments, is disclosed. It is to be understood that a similar dampersection (not shown) is provided for the other two compartmentsdisclosed. Damper sections 7 each include a pair of primary dampers 14,each of which cooperates with a dirty gas inlet 9 of a compartment insection 3. In similar fashion, damper sections 7 also are provided witha pair of secondary dampers 16, each of which controls the reverseoutlet flow of gas through a gas reverse flow aperture 11 of acompartment in section 3. In this connection it is to be noted that eachdamper section 7 is provided with a dirty gas inlet duct 17 upstream ofdampers 14 and a gas reverse flow duct 18 downstream of dampers 16.Suitable blower mechanism (not shown) is provided to move dirty gasthrough duct 17, apertures 9, into the compartments of section 3 andthrough the gas pervious fabric tubes of tube section 4. In likefashion, suitable reverse blower mechanism (not shown) is provided tomove clean gas in a reverse direction through the tubes of tube section4, through the compartments of section 3, through reverse flow outlets11 and through downstream duct 18. It is to be understood that dampers14 and 16 of each damper section 7 can be pneumatically actuated througha solenoid controlled pneumatic system in a novel preselected manner asdescribed hereinafter (FIGURE 3).

Referring again to FIGURE 1 of the drawings, it can be seen that tubesection 4 communicates with dirty gas inlet sections 3 through aplurality of apertures 19 disposed in header plate 21 extending acrossthe lower por tion of tube section 4. Each aperture 19 is surrounded bya thimble or sleeve 22 so that the lower end of a tube 23 can befastened to such sleeve with the aid of a draw band clamp 24 (notdisclosed in detail). Tubes 23, which can be fabricated from any one ofa number of suitable gas pervious materials and which advantageously aremade from a fibrous glass material capable of resisting temperatures ashigh as 550 F., are each closed at their upper I ends by means of a cap26, the upper end of the tubes being fastened to the cap with the aid ofa suitable draw band clamp 27. To maintain the tubes in verticallyextending, substantially parallel position in tube section 4, horizontalsupport grating 28 is provided across the upper portion of tube section4. Each tube 23 is suspended from support grating 28 through a chain 29fastened at one end to a plate 31 carried on the support grating. Theother end of each chain 29 is fastened to a spring 32, which in turn isfastened to the cap 26 on which an end of tube 23 is mounted. It is tobe understood that the chain, spring and tube are so sized that thespring maintains the tube under a preselected resilient tension duringgas cleaning operations, the tension being adjusted to permit theinventive tube cleaning operations hereinafter described.

Referring to FIGURE 3 of the drawings, an advantageous circuit isdisclosed for accomplishing preselected actuation of the solenoid valves(not shown) in pneumatically operated damper sections '7 and thus thetube cleaning operations of the aforedescribed apparatus in a mannerheretofore Unknown in the art of gas cleaning. This circuit includes amain supply line L L adapted to receive a suitable voltage,advantageously v. from a suitable, appropriately fused step-downtransformer (not shown). With On-Off switch 35 in closed position, camtimer CT connected across line L -L is energized to be driven so as toclose normally open contact CT for a preselected length of time fourtimes each cycle of the cam timer CT. Thus, the timer system TD1, TD2,TD3 is energized four times during such cycle of the cam timer. At thesame time, cam timer CT serves to drive, through a suitable chainlinkage, a cam programming device (not shown) which serves tosuccessively close in preselected intervals normally open switches CT CTCT and CT successively so that the dampers for each compartment can besuccessively operated by the timer system TD1, TD2, TD3, as describedhereinafter. When cam timer CT is moved to the first position wherenormally opened contact CT is closed and normally open contact CT forone section is closed through the cam programming device linked with thecam timer C1, gas cleaning operations for that section-which have beenat a suificient pressure and velocity to maintain the tubes in inflatedform-cease and tube cleaning operations commence, as a result of thefollowing. Since CT is closed, control relay CR1 in the same line as CTis energized. With CR1 energized, the two normally open contacts CR1,are closed. With contacts CRl closed, the primary damper solenoid relayPDRI for that section is energized, as is the reverse damper solenoidrelay RDR1 for that section. With these relays energized, primary damper14 for that section closes off its dirty gas inlet 9 to stop passage ofthe dirty gas stream through the compartment and through tubes 23connected with the compartment. At the same time, secondary damper 16,controlled by relay RDRl, is moved to open position to open aperture 11and the reverse flow of clean gas under suitable pressure commences. Itis to be understood that this reverse flow of clean gas is at asufficient pressure and velocity to collapse tubes 23 communicating withthe section. The length of time that the primary damper 14 is closed andthe secondary damper 16 is open is preselectively controlled by timersTD1 and TD2. The timer TD1 after it times out allows normally closedcontact TD1 to open and the timer TD2 allows normally closed contact TD2to open. This results in deenergization of solenoid relays PDRI andRDRl. The position of the dampers 14 and 16 of that section are thenreversed, with the primary damper 14 opening and the secondary damper 16closing. Tubes 23 in that section then commence to reinfiate. At thispoint, it is to be noted that at the same time that timers TD1 and TD2are running a third timer TD3 also is running. Timer TD3 is set to runfor slightly longer preselected period of time than timers TD1 and TD2.As soon as timer TD3 has run its preselected course, normally opencontact TD?) closes and, as a result of this action, solenoid relay PDRIagain is energized. This in effect causes primary damper 14 to again beclosed for a short preselected period of time, the damper 14 remainingclosed until contact CT controlled by cam timer CT opens with aresulting opening of the circuit. Thus, in effect, primary damper 14 isclosed on the reinflation cycle for a short,

null period of time. The setting of timer TD3 is such that the nullperiod commences at a point just before tubes 23 of the section arefully reinflated. Because of the inertial motion that is imparted to thetubes during the reinflation cycle by the dirty gas under suitablepressure and velocity, the tubes proceed to full inflation after thenull period commences with a gentle fluttering motion that furthercracks the cake of contaminant particles on the tubes and yet avoidsheretofore known snapping or popping action of the tubes. It is to benoted that the null period initiated by timer TD3 before contact CTopens is sufiicient to allow dislodged contaminant particles to settlefrom the tubes into hopper section 6. Once contact CT opens, the tubeshaking period for that section is complete. Damper 14 then opens againto permit further treatment of the dirty gas stream by the cleaned tubesection. After a preselected period of time, cam timer CT rotates to asecond position. This again results in closing of contact CT for apreselected period of time. In the meantime the cam programming devicecoupled to cam timer CT has moved to a second position to close contactsCT and the tubes of a second section are cleaned in a similar manner.And so, in like sequential fashion, the tubes for the third and fourthsection are cleaned and the entire, overall cycle repeated.

The invention claimed is:

1. A method of collecting contaminant particles from a dirty gas streamincluding the cycle steps 'of passing such dirty gas stream into an openend of and through the walls of a gas pervious fabric tubular collectorat a first pressure and velocity sufiicient to maintain said fabrictubular collector in inflated form with contaminant particles in suchdirty gas stream collecting on the inner surface of the Walls of saidfabric tubular collector; thereafter cleaning the collector in acleaning cycle comprising stopping the flow of said dirty gas streaminto said fabric tubular collector when a cake of contaminant particleshas collected on the inner surface of the walls thereof; passing a cleangas stream in a reverse direction through said fabric tubular collectorat sufficient pressure and velocity and for a preselected time intervalduring the cleaning cycle to at least partially collapse said fabrictubular collector and to crack the contaminant cake collected thereon;resuming the flow of said dirty gas stream into said open end andthrough said fabric tubular collector at the first pressure and velocityfor a time period less than that required to reinfiate the collec tor;stopping the resumed flow of said dirty gas into said collector at apoint prior to full fabric tubular collector reinflation to allow saidcollector to inertially fully reinflate in a softly fluttering manner;stopping the clean gas stream at a preselected point during saidcleaning cycle; and resuming the flow of said dirty gas stream into andthrough said collector at the end of said cleaning cycle after saidfabric tubular collector has inertially fully reinflated.

2. The method of claim 1, including the step of maintaining said fabrictubular collector under resilient tension to facilitate inflation andcollapse thereof.

3. Apparatus for collecting contaminant particles from a dirty gasstream comprising a housing having a dirty gas inlet means, a reverseflow outlet means, and a clean gas outlet means, gas pervious fabrictubular collector means resiliently mounted in said housing, saidcollector means having a dirty gas inlet communicably connected withsaid dirty gas inlet means and reverse flow outlet means of saidhousing, a first damper means constructed and arranged to control flowthrough said dirty gas inlet means of said housing, a second dampermeans constructed and arranged to control flow through the reverse flowoutlet means of said housing, and control means operatively connected tosaid first and second damper means, said control means including first,second and third timer means and an actuating means operativelyconnected to said first, second and third timer means, said first timermeans being connected to said first damper means to close said firstdamper means for a preselected period of time when said first timermeans is actuated to shut 01f passage of dirty gas through said dirtygas inlet means, said second timer means being connected to said seconddamper means to open said second damper means for a preselected periodof time while said first damper means is closed by said first timermeans to permit clean gas to pass through said fabric tubular collectormeans and said reverse flow outlet means of said housing to at leastpartially collapse said fabric tubular collector means and crack thecontaminant particle coat collected thereon, said first damper meansopening and said second damper means closing after said first timermeans and said second timer means time-out so as to resume dirty gasflow passage through said collector means; said third timer means beingoperatively connected to said first damper means to again close saidfirst damper means shortly after said first timer means has timed outand before said tubular collector means has fully inflated to permitsaid collector means to inertially move toward full inflation with anaccompanying fluttering movement to further crack and dislodge the contaminant particle coat thereon, said control means further beingoperatively connected to said first damper means to open said firstdamper means to resume passage of dirty gas through said collector meansafter said collector means has fully inflated, said second timer meanshas timed out at a preselected point with said second damper meansclosing and the dislodged contaminant 0 particles have settled out.

References Cited by the Examiner UNITED STATES PATENTS 1,764,861 6/1930Van Gelder -302 1,974,952 9/1934 Eiben 55-303 2,350,011 5/1944 Black55-96 2,800,976 7/1957 Pellon 55-302 2,805,731 9/1957 Kron 553772,871,978 2/1959 Webster et al 55-273 3,057,137 10/1962 Perlis et a1.55--341 3,078,646 2/1963 Leech et a1 55293 3,080,694 3/1963 Smith 552933,095,289 6/1963 Egan 55293 HARRY B. THORNTON, Primary Examiner.

GEORGE D. MITCHELL, REUBEN FRIEDMAN,

HERBERT L. MARTIN, Examiners.

1. A METHOD OF COLLECTING CONTAMINANT PARTICLES FROM A DIRTY GAS STREAMINCLUDING THE CYCLE STEPS OF PASSING SUCH DIRTY GAS STREAM INTO AN OPENEND OF ANID THROUGH THE WALLS OF A GAS PERVIOUS FABRIC TUBULAR COLLECTORAT A FIRST PRESSURE AND VELOCITY SUFFICIENT TO MAINTAIN SAID FABRICTUBULAR COLLECTOR IN INFLATED FORM WITH CONTAMINANT PARTICLES IN SUCHDIRTY GAS STREAM COLLECTING ON THE INNER SURFACE OF THE WALLS OF SAIDFABRIC TUBULAR COLLECTOR; THEREAFTER CLEANING THE COLLECTOR IN ACLEANING CYCLE COMPRISING STOPPING THE FLOW OF SAID DIRTY GAS STREAMINTO SAID FABRIC TUBULAR COLLECTOR WHEN A CAKE OF CONTAMINANT PARTICLESHAS COLLECTED ON THE INNER SURFACE OF THE WALLS THEREOF; PASSING A CLEANGAS STREAMO IN A REVERSE DIRECTION THROUGH SAID FABRIC TUBULAR COLLECTORAT SUFFICIENT PRESSURE AND VELOCITY AND FOR A PRESELECTED TIME INTERVALDURING THE CLEANING CYCLE TO AT LEAST PARTIALLY COLLAPSE